Fix build to create Windows SDK.

frog/dart-frog.gyp

Index: frog/dart-frog.gyp
===================================================================
--- frog/dart-frog.gyp	(revision 2648)
+++ frog/dart-frog.gyp	(working copy)
@@ -3,13 +3,36 @@
 # BSD-style license that can be found in the LICENSE file.
 
 {
+  'variables': {
+    # These variables are used in the creation of the .vcproj file on 
+    # Windows.
+    'cygwin_dir': '../third_party/cygwin',
+    'msvs_cygwin_dirs': ['<(cygwin_dir)'],
+  },
   'targets': [
     {
       'target_name': 'frog',
-      'dependencies': [
-        '../runtime/dart-runtime.gyp:dart',
-        '../third_party/v8/src/d8.gyp:d8',
-      ],
+      'conditions': [
+        ['OS=="linux"', {
+          'dependencies': [
+            '../runtime/dart-runtime.gyp:dart',
+            '../third_party/v8/src/d8.gyp:d8',
+          ],
+        }],
+        ['OS=="mac"', {
+          'dependencies': [
+            '../runtime/dart-runtime.gyp:dart',
+            '../third_party/v8/src/d8.gyp:d8',
+          ],
+        }],
+        ['OS=="win"', {
+          'dependencies': [
+            # TODO(efortuna): Currently the Windows build only runs using the 
+            # dart VM, so we don't depend on d8 because of v8 build issues. Fix
+            # this so that Windows can also run with node.js and d8. 
+            '../runtime/dart-runtime.gyp:dart',
+          ],
+       }]],
       'type': 'none',
       'actions': [
         {
@@ -34,10 +57,27 @@
     },
     {
       'target_name': 'frogsh',
-      'dependencies': [
-        '../runtime/dart-runtime.gyp:dart',
-        '../third_party/v8/src/d8.gyp:d8',
-      ],
+      'conditions': [
+        ['OS=="linux"', {
+          'dependencies': [
+            '../runtime/dart-runtime.gyp:dart',
+            '../third_party/v8/src/d8.gyp:d8',
+          ],
+        }],
+        ['OS=="mac"', {
+          'dependencies': [
+            '../runtime/dart-runtime.gyp:dart',
+            '../third_party/v8/src/d8.gyp:d8',
+          ],
+        }],
+        ['OS=="win"', {
+          'dependencies': [
+            # TODO(efortuna): Currently the Windows build only runs using the 
+            # dart VM, so we don't depend on d8 because of v8 build issues. Fix
+            # this so that Windows can also run with node.js and d8. 
+            '../runtime/dart-runtime.gyp:dart',
+          ],
+       }]],
       'type': 'none',
       'actions': [
         {